Which of the following is true about CODEN

(A). The CODEN system, initially devised by Charles Bishop in 1953

(B). The first five characters of the CODEN, representing the publication title

(C). The sixth and final character of the CODEN functions as a numeric check digit, calculated based on the preceding letters.

(D). Presently, current CODEN listings can be accessed through CASSI (Chemical Abstracts Service Source Index), an online database developed and maintained by the Chemical Abstracts Service under the American Chemical Society.